Common practice in raising livestock such as pigs or hogs is to sort the animals according to different weight classifications for determining which animals are suitable for being sold on the market.
There exists various known prior art for devices which aid in the task of sorting livestock. Of these devices some are purely mechanical in nature while others are electrically operated. In general the mechanical devices are either manually operated or require numerous links and mechanical parts to actuate appropriate gates for sorting the animals. This can result in devices which require a lot of maintenance or in devices which lack the accuracy required.
U.S. Pat. No. 4,138,968 to Ostermann provides a mechanical livestock sorter involving complex linkages. The sorter will respond to transient loadings from moving animals which may result in weight measurement errors. The entrance gate does not prevent the entry of a second animal, or prevent a second animal from placing forefeet on the scale platform which also results in weight measurement errors.